Heat pump



Jan. 18, 1955 E. L. GARFIELD 2,699,655 HEAT PUMP Fi ld Aug. 26, 1953 2 Sheets-Sheet l NOZZLE INVENTOR.

EdkvaPdLfiarfcel'd Jan. 18, 1955 E. L. GARFIELD 2,699,655

HEAT PUMP Filed Au 26, 1953 2 Sheets-Sheet 2 INVENTOR. Edwardllaz fiefli JTTORNEKF,

United States Patent Q HEAT PUMP Edward L. Garfield, Lutz, Fla., assignor to Typhoon Prop-R-Temp Corporation of Florida, Tampa, Fla., a corporation of Florida Application August 26, 1953, Serial No. 376,688 Claims. (Cl. 62--129) The present invention relates to a heat pump, that is, to a refrigeration machine in which the refrigerant flow is reversible whereby the machine may be used both for cooling and for heating.

More particularly still the invention relates to a heat pump which employs the usual compressor but whlch has a novel gaseous heat exchanger as well as a novel liquid heat exchanger. Each of these heat exchangers is highly efficient by itself and, used together, the combination produces a heat pump with extremely great etficiency.

The gaseous heat exchanger serves as an evaporator during the cooling function and as a condenser during the heating function and has been termed a gaseous heat exchanger because of the fact that the air flowing over this device is cooled or heated.

The liquid heat exchanger serves as a condenser during the cooling function and as an evaporator during the heating function and has been termed a liquid heat exchanger because in it the refrigerant is in heat exchange relationship with cooling or heating water.

The gaseous heat exchanger or evaporator-condenser comprises a coil or plurality of coils connected in parallel relationship and formed into an hourglass form providing a heat exchanger which eliminates the usual return bends and is therefore very economically constructed.

The liquid heat exchanger comprises a plurality of small diameter tubes located within a larger diameter tube and having refrigerant medium circulating within the smaller tubes and water in the space within the large tube, surrounding the smaller tubes. In the past, a similar arrangement has been utilized wherein, however, the refrigerating medium circulated within the large tube and water within the small interior tubes, but this has proven unsatisfactory for use in a heat pump due to the freezing of water within the small tubes.

When the two units generally described above are utilized in a heat pump together with capillary tubes interconnecting these units and connecting them with the usual compressor, a heat pump system is provided which is highly elficient, economically manufactured, and readily serviced.

It is an object of this invention to provide a heat pump having a combination of gaseous and liquid heat exchangers together with capillary connections between said heat exchangers and the usual compressor forming a highly etficient heat pump system.

It is another object of the invention to provide a heat pump having a gaseous heatexchanger which comprises a substantially continuous coil of finned tubing the coil being generally hourglass form, said coil being surrounded by a cylindrical housing and provided with a baffle plate between the smallest diameter coils of the hourglass form so that the air flow through the coil is substantially uniform over the entire area thereof and the velocity of the air is substantially constant.

It is another object of the invention to provide such a gaseous heat exchanger in which the flow of refrigerant medium may be reversed so that the device acts both as an effective collector of liquid refrigerant when utilized as a condenser during the heating function and as an effective refrigerant expansion device when utilized as an evaporator during the cooling function.

It is a still further object of the invention to provide a liquid heat exchanger in which the direction of flow of refrigerant medium may be reversed so the device acts as a condenser during the cooling function and as an evaporator during the heating function.

It is a further object of the invention to provide a liquid heat exchanger particularly adapted for use in a heat pump which heat exchanger comprises a plurality of small tubes located in a particular pattern withln a larger tube, the refrigerant medium circulating through the smaller tubes and the cooling or heating water onculating within the larger tube and surrounding the smaller tubes.

It is still another object of the invention is to provide a liquid heat exchanger in which the refrigerant medium is circulated through the small inner tubes in order to prevent damage due to freezing.

Other objects and features of the invention will be apparent when the following description is considered in connection with the annexed drawings, in which,

Figure 1 is a schematic diagram showing a heat pump system in accordance with the present invention;

Figure 2 is a vertical cross-section through a physical embodiment of the heat pump arrangement of Figure 1;

Figure 3 is a horizontal cross-sectional view of the device of Figure 2 the section being taken on the plane of the line 3-3 of Figure 2;

Figure 4 is a perspective view showing a suitable cabinet in which the operating parts of Figure 2 are mounted; and

Figure 5 is a perspective view showing the structural arrangement of the gaseous heat exchanger or evaporator-condenser, the liquid heat exchanger or condensercompressor devices being mounted together so that they may be treated as a single unit for installation in the cabinet of Figure 4 and for removal for servicing or other purpose.

Referring now to the drawings, there is shown at 10 a gaseous heat exchanger which comprises a coil tubing 11 made up of the lower section 12 which is helically wound to form a conical frustum and the upper 13 which is wound to form a 811111131 conical frustum which is inverted and mounted upon the lower coil 12. As seen in Figure 2, the coil sections 12 and 13 are preferably formed of two coils which are wound in a parallel arrangement being joined both at the bottom and the top by means of the headers 14 and 15 respectively.

The lower coil section 12 rests upon a plate 16 which has a central circular opening 17 therein to provide for the upward passage of air, the edges of the hole being bent upwardly as are the outer edges of the plate 16 forming a pan for the collection of condensed moisture. The plate 16 is preferably slightly deformed where the coils rest upon it so that it conforms to the helical shape of the coil forming a better support for the coil.

A similar plate 18 is fitted closely to the top of the upper coil section 13 and the outer edges of this plate are joined to or made integral with a cylindrical housing 20 which extends downwardly surrounding the coil sections 12 and 13 and being joined at its bottom portion to the lower plate 16. The cylinder 20 is spaced from the coil sections 12 and 13 to form an air passage between the coils and the inner walls of the cylinder.

Between the two coil sections 12 and 13 there is placed a baffle plate 21 which is circular and which is deformed in the horizontal plane so as to conform to the helical arrangement of the coil sections.

The coil 10 is thus formed into what may be termed an hourglass shape which shape together with the baffle above described provides for an air flow upwardly through the center of the lower section 12, radially outward over the finned tubing comprising the section 12 into the space between the tubing of that section and the casing 20, thence vertically upward, thenc again upwardly through the center of coil section 13 and out through the center of the upper plate 18.

As is readily seen by reference to Figure 2 the air passes over two rows of tubes and then over two rows in the the elfect of a four row evaporator.

Since for best efficiency the air flow through a heat exchanger must be uniform over the entire area and since the shape of the evaporator just above-described is such as to produce the necessary changes in the direction of of the bottom section 12 e radially inwardly and top section 13 thus giving sists ofa helieallyfo'rrned relatively large outer tube havinga water'outlet'providednear its upperend as aeeagess- 3 air flow without the use of deflectors or vanes and at a constant velocity over the entire area, there is produced a simple evaporator which-.meets the conditions necessary for greatest 'efliciency". Additionally, the gaseousheat exchangencomprisinglhefinned tubinggarr'anged in a continuous heli al 'fdrrneliminates the return bends generally required in jtheflusualfor'ni of evaporator in which straight lengths of tubing jare em'PltiYedQthiis eliminating m'any solde1red joints aridrnakingihe i device cheaper .to buildi'and'm'or'e"effective lsince .tli'e entire length of the tubi'ngffis fintie'd andjis effective for theat transfer andthe continuous'forrrt'of'the coils effects a minimum of pressure drop duringflow of refrigerantthrough thetubes.

As has been-stated, a header 14 joins the parallel coils Of'thu'SflCtiOfl lZ-Hf thebotto'rnand forms an effective collector ofliquidirefrigeranfiwhenthe device is used as a condenser jduri'rigi-lthe heating ;function. Extending through the header ,14,"ar,e' smalli liquid distributing tubes 23 'trminating inlnozzlesiwhich'extend into the ends of the individualpipes of the'lowercoilsection 12. These nozzles "serve to inject liquid refrigerant into the tubes when theco'il 10 is used-"'as an evaporator during the coolingfunctionJ The upper header -15"joins1 the two orniore pipes which form the upper coil section "IS-and isconnected by means of a'pipe24 to "a valve25f The valve 25 is shown inthepresent instance as a double piston slide valve. When the valve is 'in the'position sh'own in'Figure l pipe 24 connects'to 'the pressure side of the compressor 26 and when the valve is moved to the, other position as: shown in dotted line's'in' Figu're'l, pipe 24 is. connected to the suction s ide'of compressor 26.1

'condenser 'evapora'toror .liquidheat exchanger of the present inventionisshown inFiguresl and 2. Itcogi shown at 28 and a water. inlet provided near its lower end shown at 301 The tube27has 'aheader .31 at its upper endand asimila'rheader 32at its lower end; Within the tube 27'fthere' are placed 'l-seven small" tubes 133. which tubes'are iarrange'dinithe pattern shown particularly in Figurestl and '2, that is, .one'tube being=located on the axis of thelarge tube27, the. others being equally spaced ina circular form around the small central tube. These tubes 33 are fixed in the header plates 31 and 32' At 'theloweriend'of the large outer tube 21a chamber isrformedias' is shown in Figure. 1, the chamber being separated fr'oin'the remainder of the tub'ebymeans ofthe header32 previouslydescribedu Extending through the outer walls. of this chamberare' seven small tubes 34 which tul'aes extend-'into the lower endsofjthevtubes 33 andare tapered "forming nozzles there being annular spaces left between1the'nozzlesand the. walls of thesmall tubes 33. In a similar mann'er'a chamber. is formed-at the upper end of the tube27' by means of the header '31-this chamber bei'ngwonnecte'd by m'eansof the -pipe 35 to the valve 25"so that'it maybe connected throughthat valve either tothesuction orjcornpressionside of the compressor 26. whemtheliquid heat exehanger is operating as an evapora'torliquid 'refriger'antcollects in the enlarged tube section' 36and *is injected through the .nozzles 34 into the tubes 33;"

v It will be'noted'that'the tube .27 'has an enlarged diameteri,atyeachl'endas indicated .'at '37 and38; the headers 31and 32 beinglplaced in these large end-sections and the water connections being also placed in the enlarged end sections at points clos'to' the header plates in order to- -permit eas'y entrance and discharge of water to and from the condenser-evaporator unit.

Itiwill be understood that it has been old to utilize'a structure comprising;.a plurality of small tubes within alarge tube. .Ho'wevenin all prior structures the water has'circulated within. thev smaller tubes whereas in the presentstructure the water circulates in the large tube and v the "refrigerant within the small tubes. When used as a heat pump it. is absolutelynecessary that the refrigerant rat-her than the water circulate-withinthe small tubes in orderto prevent damage-due to freezing.- It is well known as 'a' result ,of experiencetwith water chillers that when water is circulated-- in small tubes surrounded by cold 1 refrigerant anynreductionin water circulation below a certain ;minimum while the refrigerant temperature is below- 32i F. will:cause theformation ofice crystals: withln the small tube which will then result in reduced "water flow and eventually in expansion and bursting of opening the small inner tubes. On the other hand, when the small tubes contain refrigerant, upon reduced flow in the outer tube ice crystals will be produced building outwardly on the exterior walls of the small tubes and consequently neither the inner tubes nor the-outer tube will burst.

The arrangement of the small'tubes 33 within the outer tube 2'7 is aaconsiderablefactor in securing the desired results. The important factors in arranging these tubes are the area I of the surface exposed to the refrigerantandthe-velocity of thecirculating-liquid. 'The' optimum' arrangement with respect to exposed surface is that which offers maximum surface exposed to refrigerant in the smaller tubes while maintainingthe'velocity oftheli'quid sufticiently high to-break-down the surface film and provide for effective-heat transfer from the copper surface to the liquid; The arrangement must, moreover, be such that it will remain fairly constantwhile .the entire assemblage is formed intoa coil and; it. must be suchlthat' proper 1 Water velocity "Will be secured .togetherwithfan adequate-- flew of Water. The arrangement disclosed 'provides a maximumof inside surface of ith'etsmallltubesfor proper heatexchange from the refrigerantgas tothe copper am. an adequate area for water .flow aroundth'e-tubes while at the same time providingi-sufli'c'ie'ntv velocity to breakl. down the surface'film. and provide themaxirnumuheat transfer from the copper. to the water.

As is clearly shown in .Figure .1, thenrefrigerant gas is condensed and collected intlie -header.14, flows through the check valve 38, strainer .40;fpipe .41,:capillary;42 andis discharged throughthenozzles 34-into the seven small. tubes 33 of the condenser chiller.

T he capillary tube 42 provides friction ,whichvlowers the'pressure of therefrigerant tliquid so .that when ,it Lisa. dischargedthroughfthe nozzles itfis atfthe'pressure re-r quired to'boiloff or evaporate producingrefrigeration.andi chilligg 'of the water i'which'iis circulatinggthroughiltheunit As will be clear'under the conditions discussed above the "hot'gas is 'beingforce'd through the pipe 24 byithe. compressor 26jandthrough. the evaporator-condenser. 10 T and the air 'flowingjthrough'the coils. of that evaporator-. condenser' is being {heated At this time also the-gas fiowing'through the tubes 33 of the liquid heat exchanger 27 is returned byvmeans' of pipe35 tothesuction side-of t'hc'compressor- 26."

When the valve 25 is operated tothe position indicated dotted lines ilrFi'gure-l; gas, from the comprcssorflows to the top of the'liquid heat exchanger-213s. condensed as it fiowsthrough'the small pipes 33 due to .thechilliiig-i effect of the water'andthe-condensed liquidthen settles in the bottoin'ofthe lowerendchamber.flowingtthrough the check valve 43, st'ra'irie'r 44;pipe 45,.and-.capillary 46 to the nozzles 23 inheader 14. Thus theliquidlis injected into' the evaporator-condenser :10, and expandsthereinlhe gas being returned-throughfchec'k valve 47"and fpip'es 24' and;24a to the suctionsi'deof the compresson. The'capil l' larytube 46 servesin'the same manner as does the capil-v lary tube 42 to lower the pressure of the refrigerantliq'uid so that when it is discharged through. the nozzles .23; it is at the pressure required'tofevaporate' As is-readily seenfrorn the above description when. the piston'ofvalve"25" isin one of"its-two positions namely, the full line position 'as"seen*in' Figure 1,: the system" serves to warm I the air passing -through the *coil 10 whereas :when the valve is in its dotted line "posit-ion" theirsystem-nserves toncool the air passing through' that co1 The various 9 elements: heretofore at described 51 are asesembled in a-cabinet- 49-such= asfthatzshown in"Figure'-' this cabinet-having an; opening- 50 in the side 1 thereof: and a: secondopening sl {in-1 the 'top'.thereof;: 1Coilf-10 on its mounting plate 16 mountedon=-a base plate; 52 by means ofv posts v53. The compressor 26 and thel condenser-evaporator '21'1are .als'o. mounted on.v the baseplate 52, the ent'ireunitthus' assembled ."is inserted into the*ope nin'g. 50j'injcabinet-49; and a 'cover member 54 best shownin Figure"'2 Jis' 'positione'dbver the opening.

together with the air 'directin'g -=louvcrs56; g V

Mounted inthemppempart"(if-the cabinet49is a blower" 57, of any usual form, discharging through the 51,: theeblowe'r bei'ng' driven": byamotor- 558- suitably. imounte'dcadjaeentithettblower riniihemppe'r 'part of the cabinet. As isreadily'seen, as thus assembled,

86 the device is compact, readily removed from its, cabinet for servicing and as has been described, a unit of high efficiency.

While I have described preferred embodiments of my invention it will he understood that many other modifications may be made without deviating from the principles thereof; therefore I wish to be limited not by the foregoing description, but solely by the claims granted to me.

What is claimed is:

1. A gaseous heat exchanger comprising, in combination, at least one coil of tubing, said coil comprising two sections, each section being wound in generally helical form and forming a truncated cone, the smaller diameter ends of said sections being connected together, a battle plate intermediate said coil sections and a casing surrounding said'coil sections being substantially of the diameter of the large end of said coil sections, said casing having central openings in the ends thereof whereby air is admitted to the center of said lower coil section, ows radially outwardly over said coil, upwardly through said casing, radially inwardly through the turns of the second coil section and outwardly and axially through the opposite central opening in said casing end.

2. A device as claimed in claim 1, characterized in that each coil section is comprised of at least two coils in parallel arrangement forming conical frustums, and further characterized in that the two parallel coils are connected together at their ends by means of headers.

3. A device as claimed in claim 2, characterized in that means are provided in one of said headers for injecting liquid refrigerant into said coils, said means comprising nozzles extending through said header and into the terminal ends of said coils.

4. In a heat pump, a compressor, a gaseous heat exchanger, said gaseous heat exchanger comprising a coil of hourglass shape having a casing of substantially the same diameter as the ends of the hourglass form and having a baflie at the point of narrowest diameter of the hourglass coil to compel air to flow through said hourglass coil at substantially constant velocity, a liquid heat exchanger comprising a large diameter coil through which water is circulated, said large diameter coil having a plurality of small diameter coils therein for circulation of refrigerant, said coils terminating in header plates adjacent the ends of said large diameter coil, valve means positionable to connect the high pressure side of said compressor to one end of said gaseous heat exchanger and the low pressor to said one end of said gaseous heat compressor,

at the other end thereof, means connecting said other end of said gaseous heat exchanger to said nozzles of said liquid heat exchanger, said means including capillary tubing and a check valve, and means connecting said other end of said liquid heat exchanger with said nozzles of said gaseous heat exchanger, said means including capillary tubing and a check valve whereby operation of said valve means serves to reverse the flow of refrigerant through said system and interchange the functions of said liquid and gaseous heat exchangers, said gaseous heat exchanger serving as an evaporator to chill the air flowing therethrough in one position of said valve means and as a condenser to warm the air flowing therethrough in the other position of said valve means.

5. In a liquid heat exchanger for a heat pump system comprising, in combination, a tube of relatively large diameter formed into a helix and having a header at either end forming chambers thereat, seven tubes of smaller diameter within said large tube, one of said seven tubes lying on the helical axis of said large tube and the remaining six of said seven tubes having their axes extending parallel to the axis of said large tube and arranged about said first small tube so that their centers lie equidistant on the circumference of a circle whose center on the axis of saidlarge tube, the relatween said headers,

means for admitting water to said large diameter tube References Cited in the file of this patent UNITED STATES PATENTS 1,206,789 Adams Dec. 5, 1916 1,581,384 Chester Apr. 20, 1926 1,802,396 Taylor Apr. 28, 1931 2,172,129 Philipp Sept. 5, 1939 2,334,219 Roth Nov. 16, 1943 2,342,566 Wolfert Feb. 22, 1944 2,388,314 Eisinger Nov. 6, 1945 2,589,384 Hopkins Mar. 18, 1952 

